11 × 44 = 484 g
mol × molar mass
The atomic mass on the periodic table represents the sum of number of protons and number of neutrons.
Atomic mass = Number of protons + number of neutrons
Hope this helps!
The answer is B. Molecules move more quickly as temperature increases.
When Allmond molecular motion stops, that is considered absolute zero. That does not mean that it cannot get colder, disapproving A.
C is just wrong.
D says when molecular motion stops the temperature STARTS to decrease, it was decreasing before it got there.
The radioactive decay obeys first order kinetics
the rate law expression for radioactive decay is
Where
A0 = initial concentration
At = concentration after time "t"
t = time
k = rate constant
For first order reaction the relation between rate constant and half life is:
Let us calculate k
k = 0.693 / 72 = 0.009625 years⁻¹
Given
At = 0.25 A0
time = 144 years
So after 144 years the sample contains 25% parent isotope and 75% daughter isotopes**
Simply two half lives